Flexible fiberoptic and video endoscopes have permitted access through the duodenum for diagnostic and therapeutic biliary endoscopy. Therapeutic procedures usually require sphincterotomy for operations such as stone extraction and placement of stents.
To perform a safe and successful sphincterotomy (selective cannulation) of the bile duct is required. Occasionally special techniques and devices are required to gain access. Even with operator skill and experience, this procedure can be difficult. FIGS. 1A and 1B illustrate a front and cross-sectional side view, respectively of a papilla of Vater 50. The bile duct 52 and pancreatic duct 54 almost always exit at a common orifice 56 in the ampulla of Vater 50. Their union is variable but usually just proximal to the orifice 56 in the sphincter of Oddi 58. The anatomy of the site usually favors entry of the pancreatic duct 54 when cannulation is attempted. During the procedure, the operator must blindly probe the ampullary orifice 56 in the direction of the common bile duct 52 to gain entry.
Because of the anatomic variables and the minute size of the orifices 52, 54, common bile duct 52 cannulation is occasionally not possible. Furthermore, excess manipulation of the sphincteric mechanism 58, inadvertent pancreatic duct 54 cannulation, guide wire probing, and repeated injection into the pancreatic duct 54 while attempting to selectively cannulate the bile duct 52 greatly increases the risk of increase the risk of pancreatitis, a serious complication of ampullary cannulation. Another risk factor for pancreatitis can include the heat produced from electric cutting devices.
When ordinary measures for selective biliary duct 52 cannulation fail, several alternate methods can be used to increase success. Needle-knife sphincterotomy has been the predominant technique used. In this procedure, a heated wire is used as a knife. One drawback to this technique is that the needle knife is difficult to control and can provide an improperly placed and larger incision than is desired. Another method includes the use of the pre-cut papillotome, which includes a cutting wire exposed at the tip of the device. The cutting wire is used to incise into the roof of the papilla to expose the bile duct orifice to facilitate entry. More recently, another method has been described using a standard papillotome to pre-cut through to the bile duct with the papillotome in the pancreatic duct. In another method, the liver can be punctured and a guide wire passed through the bile duct 52 and papilla of Vater 50 into the duodenum where an endoscopist can gain assisted access. These methods can increase the risk of pancreatitis and other complications.
The biliary sphincter scissor is a miniature device for cutting tissue in a sphincterotomy procedure. The scissor can be inserted through an endoscope and can include a stationary cutting surface or blade and a moveable or actuated cutting surface or blade. The stationary blade is fixed relative to a distal end of a sheath and has a small size so as to fit into the papillary orifice. The actuated blade is opened and closed by an actuating mechanism, preferably with the blades opening in the distal direction. The scissor is fixed to a shaft having a sheath which surrounds that portion of the actuating mechanism extending from the proximal end of the device to the scissor. The shaft is flexible to accommodate the bends in an endoscope that has been inserted into the duodenum. The distal end of the shaft bends so that it can be directed through a side opening or aperture in the endoscope adjacent a viewing window. An elevator in the endoscope can be used to rotate the distal end of the scissor device relative to the endoscope axis. The actuator can include a wire attached to a control which pushes and pulls the wire to activate the actuating blade. The length and diameter of the device permits it to be passed through the working channel of an endoscopic device such as a duodenoscope.
In order to provide a desired orientation of the scissor with reference to the papilla when it protrudes from the duodenoscope, the distal end of the shaft can have a flexible arc-shaped curve. The curve defines a first plane which the surgeon can use to orient a second plane in which the scissors open and close. In a preferred embodiment, the plane in which the scissor blades function coincides with the plane of the curved shaft. In another preferred embodiment, the plane of scissor operation is oriented at an angle between 5 and 20 degrees relative to the plane defined by the curved shaft. A preferred embodiment can also include a rotationally stiff shaft such that the surgeon can rotate the handle of the device through a given arc and thereby cause rotation of the scissor plane through the same arc to achieve proper orientation of the blades relative to the papillary orifice.
The technique of biliary scissor sphincterotomy can include a series of steps following endoscopic placement of the scissor. The stationary blade of the scissor is inserted a short distance (2-3 mm) into the ampullary orifice. Usually there is only a short common channel after which the biliary and pancreatic ducts diverge. The scissor blade is directed toward the bile duct while remaining in the common channel. Next, the common channel is cut open with the scissor by movement of the actuated blade through the tissue. Then the lower blade of the opened scissor is advanced along the incised channel in the bile duct direction and small xe2x80x9cnipsxe2x80x9d are made to expose the opening of the duct. It is expected that only a few millimeters, approximately 4-6 mm, need to be opened in this manner, allowing subsequent select biliary cannulation with a standard catheter, guide wire, or sphincterotome. Adapting the scissor device to apply an electric current to the tissue during cutting provides for cauterization of the tissue thus enabling for a more extensive sphincterotomy.
Pre-cutting with the biliary sphincter scissor eliminates or reduces the risk of pancreatitis by avoiding papillary manipulation, contrast injection, and heat from cutting devices. Significant bleeding is not likely owing to the presence of only minor vessels in the incised area and the need for only a short incision.